Posted
by
Zonk
on Saturday May 13, 2006 @02:39AM
from the road-to-the-fusion-reactor dept.

Dipster writes "The Japan Atomic Energy Agency has announced that its JT-60 Tokamak has almost doubled the previous record for sustained plasma production, which is now sits at 28.6 seconds. It is believed that once 400 seconds can be achieved, a sustained nuclear fusion reaction will be possible. While 28.6 seconds is a long way from 400, it raises hopes for what will be possible from the ITER reactor, expected to be finished in 2016."

With only these two data points (16.5 sec in 2004 and 28.6 in 2006) we can get 400+ seconds by the year 2018. While two years behind the 2016 date, is probably ahead of schedule if I know anything about building schedules.

Movies have let me down. I was supposed to be flying around Mars on my Mr. Fusion powered space car 15 years ago.

If you assume that they'll only be able to increase the time linearly, then yes, it's about fifty years.If you assume that they'll be able to keep refining the technology and keep doubling the time every two years, then we're only looking at 7.6118259 [2*log(400/28.6)/log(2)] years.

If you go by the progress rate of existing fusion devices starting from 1965, it goes right back to 50 years (52.3 specifically, but who's counting?)

Generally you want to stick to linear when something has been linear throughout

If you go by the progress rate of existing fusion devices starting from 1965, it goes right back to 50 years (52.3 specifically, but who's counting?)

2006 - 1965 = 41 years.

If we're calling the last period an anomaly, and indeed it was simply linear progression from 1965 to 2004, it was only 39 years (2004 - 1965), and they only got 0.36667s a year. I would be willing to bet (and I would love to see the data that disproves this) that when the research first started the scientists involved got milli- or micro

Does anyone remember a short science fiction story that basically had that as a premise? I can't remember what it was called or who it was by, but the idea was that a civilization built a generator that provided wireless power distribution throughout not only all three dimensions, but forward into the fourth as well. So basically as soon as it was turned on, you'd have power for the rest of eternity, even if you shut it down.The story used this as a device to show how easily people "forget the development,"

1. Q: Do you believe advancements in science are made in linear progressions? (and can be projected as such) I might take one big jump in a short period of time to get near the target, then a longer period of time to finish. But I wouldn't trust linear projections. Besides, that's what we have the media for, particularly local affiliates.

2. All projects, at least, in software, are 90% done.
If someone asks you the status, the answer is "90%".
Does anyone know what it it is for physics, or engineeri

until fusion power can be put into production? I know a lot of advances have been made in the last few years, small scale fusion using pyroelectric crystals and such, but really how far are we from the goal? Can anyone in the know comment?

I know its pretty unreasonable to ask "when is technology x coming out," but a rough order of magnitude (are we talking 10 years? 100?) has got to be doable.

Also, if we do get large scale fusion, is it really going to be cleaner and safer than modern fission plants?

"Also, if we do get large scale fusion, is it really going to be cleaner and safer than modern fission plants?"

No meltdown risk...

No long-lived waste products...

No dangerous fuels...

Likely no immediate danger of weapon proliferation...

And you have to ask if it's safer?

Just so we're clear, fission power is reasonably safe already (provided the reactors are well designed and maintained, and provided that the waste is reproccessed). All of the dangers of a fission plant are outlined above, and they're not that bad when compared with the alternatives. Fusion has none of those dangers; the nuclear reaction ceases if the reactor vessel loses confinement, the major waste product is helium-4 (which is commercially useful and chemically inert), reactor irradiation is minimal, and can be limited further by careful choice of building materials, the fuels are safe to handle, and there's no way to make a bomb out of the reactor technology that we know of yet.

That's not to say there are absolutly no problems. Even with careful material selection, the reactor vessel will become slighly radioactive over it's lifetime. But safer and cleaner than fission? Yes, and by an order of magnitude at that.

The waste doesn't have to be especially long lived no matter what method of recycling you use. It's only when you don't recycle the waste that you run into problems.However, consider what we're comparing to. The waste product of a fusion reaction (using deuterium and tritium fuel) is helium-4, which is safe and useful. The only radioactivity is through neutron activation, which isn't precisely "waste", and isn't even close to a fission plant.

Now I freely admit that things may have changed in the 7 or so years since I quit my Phd in plasma physics, but back then that simply wasn't true. One of the major byrpoducts of a fusion reaction is (was) a pretty steady flux of neutrons. Being neutral, the only way to contain it is to absorb it. This shielding will become radioactive, and will need to be replaced periodically. It is inevitable that eventually, the entire reactor will have been damaged to the point of having to be replaced; it will all also be radioactive.

Now it's true that the half-life of the irradiated components is much, much shorter than that of the waste products of fission, and (imnho) fusion is absolutely the way to go long-term for nuclear power. However, I really don't think it's true to say "reactor irradiation is minimal".

Like I said though, it's been some time since I last really looked at this, so it's possible that progress has been made. It's also not impossible that I'm mis-remembering things (or simply misinterpreting your meaning), of course.

When comparing to a fission based reactor, perhaps my use of the word "minimal" was a tad skewed.

Remember that the object of comparison here has the same issue with neutron irradiation (ie, even ignoring waste products, a fission reactor core will become irradiated over time, as will the coolant in the heat exchangers). In addition to the neutron problem, which applies to both fission/fusion, you've also got to consider direct radioactive contamination from the fuel/waste. At least with a fusion reactor we can eliminate (or reduce) the risk of elements like strontium-90, since we get the option of choosing what radioactives we want left over at the end of the plant's life when we build it.

But I cede the point that, objectively, the degree of radioactivity in the core of a decomisioned plant would not be "minimal" by human standards.

If the article were correct, and the "best that we can hope for without massive shielding" scales as stated, why don't astronauts all quickly die? Neutron flux should scale the same as anything else (1/r2), and they sure don't have massive shielding on the ISS. So if we were to build a "little sun", someone standing at a point from which the energy per square meter was the same as that from the sun in LEO, they should need no more protection than someone on the ISS, which should be cheap and easy to prov

Where did you see anything relating to a phrase "best that we can hope for without massive shielding"?

The linked article (and specifically the portion which you excerpted), were discussing the lower bound we could expect for neutron flux. When something is "bad" then the lower bound is, by definition, "the best that we can hope for".

However, the article did so (rather disingenuously, I thought) in terms of a person standing near such a reactor without any shielding. This is clearly nuts. Anything tha

Even taken in the awareness that the device causes irradiation of its constituent materials, when you consider the case of a fission reactor, the irradiation is minimal. Most of the emitted radiation from a fusion device is absorbed back into the fuel cloud, causing a change in the constituent gasses, slightly lowering the efficiency of the fusion process, and leading to trace amounts of odd output elements (usually carbon or lower on the periodic scale, but very rarely above the sqaure root of iron; in th

I would tend to assume that a conventional fission based breeder reactor would be cheaper and easier to build if you want plutonium. Just getting fusion to work won't make it cheap or widespread right away after all, and by the time we have it, making breeder reactors should be old hat for countries like Iran. Also, a fusion plant will presumably be more complex that a fission one, and therefor harder for scientists and engineers working in third wourld countries to repurpose.As for tritium, it has a half

Well, if you want to take the article at face value, probably somewhere in the 2020's. I'd guess 2025-2029 at this rate. Perhaps faster if we really have or are about to hit peak oil as some have claimed.

And I'm not just being flippant, though the answer has been 50 years for the last 30 years or more.

ITER isn't going to be operational until 2016 at the earliest, and it's an experimental reactor not expected to be a net energy producer. Based on operational experience with ITER and IFMIF (for which construction has not even started), another experimental reactor will be designed and constructed with the goal of net energy production. Perhaps that might be operational by 2035. And if it works well enough, it's *remotely* possible that a commercial reactor could be designed and constructed, and be operational by 2055.

When all is said and done, fusion recactors are expected to produce *slightly* less expensive electricity than fission.

The big win with fusion will require a major theoretical breakthrough rather than simply carrying the current plans to their logical conclusion.

Also, if we do get large scale fusion, is it really going to be cleaner and safer than modern fission plants?

In general it's reasonable to expect that they'll be cleaner and safer. There is no possibility of a runaway chain reaction; the reactor only contains enough fuel at any given time to operate for a fraction of a second, vs. months or years for a fission reactor. If the fusion reaction containment fails, the reaction quickly stops, without serious damage to the reactor and without any abnormal leakage of radioactive material. A fusion reactor can't "melt down".

A fusion reactor will produce a greater quantity of radioactive waste (crumbling radioactive shielding and structural materials after years of exposure to high neutron flux), but fortunately the waste will have a very short half-life so it won't be dangerous for too many decades, and will thus be easier to store. No need to worry about safety over geological time scales, or about whether our descendents will be able to read warning signs printed in 21st century languages.

If the fusion reaction containment fails, the reaction quickly stops, without serious damage to the reactor and without any abnormal leakage of radioactive material. A fusion reactor can't "melt down".

Unfortunately, like most reactors, it will collapse into a pile of rubble after exactly 50 years. Which is why I prefer to use hydroelectric power...

"[How long] until fusion power can be put into production? I know a lot of advances have been made in the last few years, small scale fusion using pyroelectric crystals and such, but really how far are we from the goal? Can anyone in the know comment?"

I know its pretty unreasonable to ask "when is technology x coming out," but a rough order of magnitude (are we talking 10 years? 100?) has got to be doable."

Depends on how much money gets thrown at it. If ITER shows promise, and there's really no technica

It it worth noting that the progress made in fusion research has been HUGE throughout the past 3-4 decades [jaeri.go.jp] and while the next step is more difficult than the last we aew still making steady progress. JT-60 HAS attained a confinement quality in the deuterium-deuterium shots it has taken which are VERY good, so good that if they were done with deuterium-tritium mix they would firmly place JT-60 in the breakeven parameter space very near the ignition regime (they have not "gone DT" due to pain in the ass handling issues with the radioactive tritium). There is also always hope for a shocking surprise breakthrough too (but don't hold your breath). For example, 10 or so years ago, it was though there was no way you could get around having to build immensely expensive [llnl.gov] multi-hundred beam multi-MEGAjoule laser systems in order to make inertial confinement fusion [wikipedia.org] work. Then along comes a cute little trick called Chirped pulse amplification and suddenly you can start talking about petawatt lasers being used to reduce the overall cost of the machine by 10 fold (fast ignition fusion schemes [oemagazine.com]! That's why science is so great, there is always hope something better is just around the corner waiting to be discovered.

Also, Tore Supra has achieved discharge durations in excess of 200 seconds since 2002 and has more recently had shots in excess of 360 seconds (6 minutes). Of course Tore Supra has a significant advantage over most other tokamaks in that it has superconducting toroidal field coils, giving it a steady state toroidal magnetic field. My experience in working with these machines is that on most of them the toroidal magnetic fields seriously handicap their performance due to the massive power requirements of g

It isn't a question of how long. It is more a question of dollars.It is often said that 20 years ago, the physics community estimated that they could have reactors working in 20 years. People usually ignore that this was only the first half of the estimate -- the other half was the level of funding needed to achieve the result. Needless to say, they received a small (and still shrinking) fraction of the funding they said was necessary, and the result is unsurprising.

as someone who worked in the energy generating business i hope fusion comes sooner rather than later!the price of oil and gas are going thru the roof, and these two fuels are what keeping the base load plants running here in ireland (and most of the rest of the world with notable exception of france)

theres alot of buzz around wind power nowadays but alot of people dont realise that with average 20% availability (compared to 80-90% of base plants) wind power
just doesnt cut it, and u need to have for

The greens (and other similar political groups) scaremonger against nuclear because it is (according to them), the greater of all the available evils.If you want nuclear to succeed, you need to find a greater evil, for example:"Scientists have released details of a discovery last month that when a tiny adorable kitten is poked with something pointy and sharp, an incredible amount of energy is released, many many orders of magnitude more energy than the kitten would consume in food during its entire life.

If you want a greater evil, it's coal. It's by far the most widely used fuel for electrical generation in the US, and it's more evil than poking kittens. Coal can almost be considered a default choice for electricity because it's cheap, plentiful, and most environmental costs are externalized.

I agree, and I wasn't implying that the 'fear' of nuclear is rational.But, the thing about nuclear is the potential for big accidents. The effects of a nuclear accident can be around for centuries.

There are nuclear reactor designs around now that are 'passively safe', where if something goes wrong, the design is such that it automatically slows down (eg instead of the nuclear reaction getting faster with heat, it gets slower). Many of the historic concerns for getting energy by splitting atoms are no longer

Have you ever tried to count the neutrons that come off a fusion reaction? If you do you will see that there are so many that the _best_ use of fusion once we get it will be to operate as a breader for U239->Pu239/Pu240 production or th232->U233. These are viable fuel cycles.The short of it is that fusion is rather dirty - just as bad if not worse than fission and the reason is because of all of those neutrons that are released.

India has proposed a combined hybrid fission/fusion reactor as have many others. The funding for India's new SST-1 http://www.ipr.res.in/sst1/SST-1.html [ipr.res.in] superconducting tokamak was secured under this pretext.

Call me ignorant, but what's the Irish objection to nuclear power?I don't get it. You'd think the Greens would be all over nuclear (fission) power. It's clean, and the only problems with it are ones that can be solved: meltdown and the production of waste are both manageable, and with a little effort and ingenuity. The risk of meltdown has basically been solved by new reactor designs, as I understand it.

The problems in coal and oil power are not solvable, namely the CO2 emission and the fact that we're goin

I'm not so sure that hydro is tapped out. They've started to talk about a tidal barge across the Severn Estuary again. If this got past the conservationists it would supply 25% of the current UK power demand. Not a single city, but the whole country. Of course it will never get built until there is £50B lying around that the government can claim, and all of the local residents / environmentalists have died. The irony is that not building it is contributing to the destruction of those habitats anyway.

But, progress is being made, maybe the rate of progress is a lot slower than anticipated. But it's clear physicists are getting closer and closer. The public needs to be patient and not cut off funding. Just because the 50 year prediction was wrong doesnt mean that this is a fundamentally impossible acheivement, as we can see, progress is being made.My main concern is the current environmentalist movement which doesnt want humans have a decent quality of life with cheap access to energy. They are stuck on

Modern commercially available solar panels, depending on type, pay off their production energy in 2-5 years, and last 20-30 years.Modern windmills turn at a whopping 18rpm, slow enough for birds to clearly see and avoid. Their appearance is subjective, but I kinda like 'em. Their production may not be pollution-free (after all, NOTHING is) but in terms of power produced per unit of pollution, they are the standout winner across the board right now.

No argument with any of your points except for the bird one again-- yes, the tips are moving at 80mph or so. Birds will hit them, but so far, the studied incidence is lower than the collision incidence with plain old buildings or automobiles. They are quite slow enough to avoid, much like you could cross a street between cars going 80mph, with a significant, constant gap between them.The average number of bird casualties per windmill per year is less than two. The trainwreck design and higher casualties

Fusion isn't necessarily clean, though probably a lot cleaner than anything else. It needs a lot of radiation shielding and greatly complicates dismantling because those shielding elements and everything in side the shield is fairly radioactive.

Fusion research is one of the only promising research fields whose funding has decreased substantially over the years. In 1970 it was predicted that ITER would be online in 1995, with a demo commercial reactor in 2005. Given that funding was cut once the oil crisis was over, is it reasonable to expect all deadlines to remain the same? In any case, now that construction has started on the ITER site, we are definitively 10 years from an net positive energy balance plasma, following ITER's research, speculated

ITER is designed to produce approximately 500 MW (500,000,000 watts) of fusion power sustained for up to 500 seconds (compared to JET's peak of 16 MW for less than a second). It is a significant amount of power for a fusion research project; a future fusion power plant would generate about 3000-4000 MW of thermal power. Although ITER will produce net power in the form of heat, the generated heat will not be used to generate any electricity.

As a bachelor degree student in physics in the 70's and early 80's, fusion research was on of the 'hot' topics. The tokamak was the predominant fusion plant, but other fusion reactors were being investigated. In those days we measured sustained reaction times in milliseconds.
Obviously I haven't been keeping up, 'cuz 28 seconds sounds like a lifetime to me now.

Forgive me if I'm missing something completely obvious here, but why is progress in fusion research still progressing so slowly? Sources generally cite estimates in the 2050-2060 range for when we'll be actually using fusion power.

The actual research itself is relatively unpredictable, I understand that. But when I read that completion of the ITER (the way I see it a relatively straightforward job, I assume the blueprints are already completed) is still 10 years away, I wonder how much time could be shaved off that estimate, as well as the ~2050 estimate, if (a lot) more money were put into fusion research.

If nuclear fusion has the potential to provide a clean, efficient, lasting energy source, and thereby eventually solve the energy crises, it would seem to me that investing a far larger amount of money than is being put into it today would be a very good investment if that could mean nuclear fusion can be used a few years earlier. I think ITER's cost is estimated at about EUR 10 billion, which is a lot of money, but in the grand scheme of things (I think the world GDP is somewhere around 50 trillion) it's tiny. And seeing the large potential for creating armed conflict there is in energy shortages even these days, I'd say getting fusion sooner rather than later may very well be a real matter of life and death.

However, when I hear discussions on the energy crises, the efficiency of solar/wind/water power, whether more nuclear fission reactors should be built, fusion isn't even mentioned, let alone considered by politicians for larger investments. Is it simply because it's so far away, and that for the most of us, only our descendants would benefit from those investments?

Once again this is a serious question, I'm no expert in any of this so I honestly don't know.

Some humour to start: " Sources generally cite estimates in the 2050-2060 range for when we'll be actually using fusion power.", SimCity 2000 is NOT a source!I think the slow investment in fusion, bio-diesel, eco-friendly widget X, or sciencey cool widget Z is because it is just that, INVESTMENT. Investing, even from the government, is a matter of getting something back from that investment in a reasonable time.

I am inclined to agree with your guesstimate of 2050 for viable energy from fusion. So we would h

Cynics suggest that the research grants and opportunities to build empires will vanish if the problems get solved.

Well hey, if we're going to play devil's advocate then let's see how far down the line we can go. Is it possible that investment into the fusion project will increase once someone figures out how to create an empire in a world with fusion? Look at how the DMCA was passed way in advance of a lot of the problems it addressed; we should be thinking of what problems fusion would create and legislate

Short explanation:Try building a heating system or oven entirely out of ice, without melting the ice in the process.Long explanation:The problem is threefold:1) It's very hot (millions of degrees (Celsius)). So you need very good isolation and confinement, or it will boil your facility and cool down itself to the point where it's useless. You have something which is generating energy, it is very, very hot, and therefore contains very fast particles, that want to travel in a straight line, "filling" the vacu

Since you give the impression to know a bit about it, another question for you (or anyone who feels like they have an idea;-)): What factors/elements of the equation do you think are directly responsible for making it take so long to bring fusion power to the masses? To come up with clever solutions you mainly need clever people, not necessarily a lot of time.

I get a strong sense that of the required 40-50 years I usually read about, only a small fraction will be actually about people thinking up clever s

I'm mainly rehashing what I learned when I visited JET a couple of years ago. I'm more kind of an astrophysics engineer myself.As far as I understand the whole thing is mostly an engineering issue. With something like an Apollo Moon project style approach it could maybe be done in 10 years. It would have to be a massive national or super national effort.

I think history has shown us that especially where efficiency is the main concern, like it seems to be with the whole fussion problem, it will just take tim

Forgive me if I'm missing something completely obvious here, but why is progress in fusion research still progressing so slowly? Sources generally cite estimates in the 2050-2060 range for when we'll be actually using fusion power.

Well, wasn't the US supposed to only be using HDTV by when 1997? 2000? ROTFL. Long range predictions tend to be wrong, but people forget about that.

On the other hand, 2050 is long enough for the current generations to not care. (I won't have many years left in 2050). All lead

In terms of science investment, fusion has recieved quite a lot of funding. People are simply not willing to pay very much for science which may not work out in the end. Why do we have to have cancer research fundraisers? Can't someone just give them what they need to cure it?There are a lot of technical reasons to look for power sources other than fusion. One reason is, it's radioactive. There's far less radioactivity than in fission, but you still end up with a lot of radioactive waste, and you still

I always wonder why Tore Supra is ignored here or in the US Wikipedia.

As far as I can read, it seems rather impressive. Their record for plama duration is... 390s ! More information on the fusion-dedicated French CEA (Commissariat à l'Energie Atomique) site [www-fusion...que.cea.fr] (in English).

But the question is honest: what have achieved the Japanese? Is their plasma self-sustaining? Have they reached break-even point and maintained it during the whole 28.6 seconds?

Anyway, just give a look to the CEA site: from pictures to videos, plenty to discover there.

I'm ignorant of Tore Supra's parameters, but discharge length can be extended by sacrificing other parameters of performance. The key is to get a long discharge with full plasma current (in the case of a tokamak), high electron and ion temperature, and good plasma density.

Certainly these parameters are quite good. They aren't what JT-60 or JET can get, but then the machines are designed for very different purposes. The source of Tore Supra's lengthy discharges are it's superconducting magnetic field coils.

There are lots of reasons this wouldn't work. Off the top of my head:
- Insufficient technology to build a spherical structure of that size.
- Even at miles in size, the detonation of a hydrogen bomb would yield huge overpressure waves, and arch construction is good at being compressed inwards, not outwards.
- Hydrogen bombs requires a fission reaction to detonate - it would be more efficient to fission the fissionables in breeder reactors.
- What, exactly, are "energy collectors?"

Actually, I think we certainly do have the technology - if you modify the parameters a bit:

First off, the spherical chamber: Do what Operation Plowshare did, use a nuke to build the chamber by detonating it underground. I bet that if you mined ventilation shafts at the near "edge" of the explosion, you could vent off the overpressure. The heat from the explosion would sinter the rock together. All that would be left would be to send in some remote-controlled mining equipment to "smooth" it out. You aren't t

I predict that we will have fusion power not before oil reserves are exhausted - too much money/politics/everything involved. Can't be allowed. If we have fusion power production tomorrow - what would all those arabs do? Huh?

You moron. It's not too much money, it's too much oil. Oil & coal are so rediculously cheap right now that it's almost pointless to try anything else. Ok, oil costs more than some people would like to pay at the pump, but they're still buying it. Is it really reasonable to demand that "natural resource-x" that happens to be extremely useful continue to be sold at the same price despite finite supply and artificially limited exploration?

Nonsense. The TORE SUPRA reactor in 1996 was at 20% over break-even, and ran for a hair over two minutes. The Large Helical Device isn't even a power plant - it's a stellarator used as a fusion plasma confinement device for high-energy materials research. Nobody's drawing any current from it at all, and stellarators cannot break even. You don't know what you're talking about.

Checking a couple of journals reveals that the JT-60 discharge duration can be as long as ~65 seconds while the ELMy H-mode, which ITER will operate in, lasted for about 30 seconds. The article might be referring to this or it may be referring to some of the 30 s discharges that JT-60U has, I'm not sure.
Something else that is interesting is that there are plans to further upgrade JT-60U (U is for upgrade from JT-60) to JT-60SC which will include superconducting magnetic field coils. I haven't been able

come on already. we have been hearing tantalizing bits of data about fusion and tokamaks for YEARS AND YEARS now. When are ya gonna figure it out already??;)

(i'm mostly being facetious, i know it's a so-called "hard problem"... but you guys really have some beers waiting for you if you figure this plasma fusion thing out and get positive net energy flow...)

I hope those are time travelling beers. Maybe we can use the TORE SUPRA [www-drfc.cea.fr] to power them, which achieved 20% above break-even in 1996.

In as regards your being facetious, I find it quite amusing that the word doesn't mean what you think it means, but that as a result of your mistake the impression you give is what the word actually means. Witness:

Everytime I read any Fusion based posts it really allows me to see how ignorant a LOT of people are. Some seem pretty close, but get caught out as being bulls-hitters somewhere in their post

K, I am doing a PhD in Fusion in one of the best fusion plasma groups in the world. I would be happy to answer any questions.

Not having a go at any random posts, but just a few mistakes I didn't see get checked. 1. Yes Fusion is safe, very safe, super safe. Safe!! You can ask me why, but no-one ever seems to pay attention, or even understand.

2. Fusion weapons have been around since at least the 1960's! Hydrogen bombs. Kinda like 50 years too late to be scared about that one.

3. Would you like to know why fusion isn't here yet? It's very difficult! It's not an oil conspiracy!! The people in fusion are academics and believe me when I say they don't generally give a crap about money. They are smart people concerned with the environment.

4. Why is it difficult? You can't switch JET or MAST on for too long because of Ohmic heating. It basically implies that super conducting (very $$$!) coils are needed to get around this problem. ITER will be one of the first reactors to have all superconducting coils.

6. Anything else? Yes, actually. We are literally making it up as we go along. How many people know exactly what a plasma is? I mean what defines it? It's Debeye length? Collisionless? Quasi-neutrality? What do any of these terms mean? If you don't know you probably aren't qualified to talk on fusion. Plasma physics is relatively to the rest of science an incredibly new and young field and it is extremely varied.

There's lots and lots going on in fusion. I apologise for the lack of links but i'm typing quickly and don't have time. Suffice to say, everyone in the fusion community is very enthusiastic about it. It is getting more and more (international) money all the time. The Chinese and Japanese are involved, not to mention India and the most of the West.

On an interesting side note. The thing that mainly held fusion back wascan you guess?AMERICA!! Constantly pulling in and out of the project. However, now that the Indians are involved the funding is about 110% of what is required. So if the yanks pull out again then they will fall behind because no-one else cares anymore and we'll have enough money to, and we will, continue.

Once concern I have about fusion is that long before it is commercially feasible for electric power, it will be a powerful neutron source for, dunno, making plutonium.

I guess a device that requires funding and the best scientists from all over Europe, U.S., and India is not going to some rogue state or into some terrorist camp. On the other hand, the big sticking point for fission power is plutonium and proliferation, and a fusion reactor would be one powerful source of neutrons. If a working fusion rea

Can someone tell me what it costs to obtain the fuel needed for fusion ? I hear that we get duterium from sea water, where do we get tritium from & how ? OK: once fusion really takes off it is likely that demand will result in a drop if cost/kilogram, but what is today's price ?

I hear that there is enough duterium in sea water to provide enough for (essentially) ever, what about the tritium source ?

Perhaps, but when your fuel source is the most abundant substance in the universe, there's "close enough for engineering purposes."

Yes, and 640k ought to be enough for energy. Engineering is the science of finding new ways to suck down resources at unprecedented rates. As soon as the power's available, we'll find a way to make it scarce again. Hell, just imagine the look on the face of the Schoellkopfs 100 years ago, whose two cutting edge hydroelectric plants on the Niagara Falls were producing about 26

Actually, it's a slightly poor summary. Obviously we can sustain a plasma for >28 seconds (neon signs for a start!). I personally have operated a 'farnsworth fusor'with a sustained fusion lasman of some minutes duration.